1. Field of Invention
The disclosed subject matter is in the field of insulated drinking cups.
2. Background of the Invention
Hot beverages sometimes require insulated containers in order for people to hold the container without experiencing discomfort due to a temperature gradient across the container wall. Non-insulated containers allow heat to conduct through the material of the container and allow the outside of the container to get hot while the contents of the container lose heat. Insulated containers exist that are capable of achieving a proper level of insulation, but such known containers are expensive or difficult to manufacture, difficult to stack, inefficient in reducing heat loss, waste construction materials, or possibly present a danger for consumers. The predominant means of drinking hot beverages in a container is to provide an outer sleeve that does not conduct heat from the main container to the outside of the sleeve. Another predominant method is to provide a cup composed of foam or plastic that keeps the outside cool enough to hold. Both means are costly or inefficient. Adding a sleeve onto a paper cup involves a two-step process involving two components resulting in large inefficiencies. A foam or plastic cup, which eliminates the sleeve, is expensive to manufacture and may also release chemical substances when heated at high temperatures. Thus, a need exists for safe insulated containers that are inexpensive to manufacture, efficient in reducing heat loss, not wasteful of construction materials.